JP2021507447A - Anion exchange membrane for redox flow batteries - Google Patents

Abstract

A flow battery having at least one rechargeable cell is disclosed. At least one rechargeable cell can include an anodic fluid compartment, a cathode fluid compartment, and an anion exchange membrane positioned between the anodic fluid compartment and the cathodic fluid compartment. The anion exchange membrane can have a thickness of less than 100 μm and a steady diffusion rate of less than 0.4 ppm / hour / cm2 with respect to the cation species in the electrolyte of the rechargeable cell. A method for facilitating the use of a flow battery, which comprises a step of preparing an anion exchange membrane, is also disclosed. Also disclosed is a method of facilitating charge storage, comprising the step of preparing a flow battery. A method for producing an anion exchange membrane is also disclosed. [Selection diagram] Fig. 1

Description

Mutual reference to related applications This application is a US provisional application filed on December 13, 2017, entitled "Synthesis of an Anion Ion Exchange Membrane for a Redox Flow Battery Application". US provisional application No. 62 / 598,135 and February 2, 2018, entitled "Tailoring Anion Ion Exchange Membranes for the Application of Redox Flow Batteries". Claiming the priority of Section 119 (e) of the US Patent Act over Application No. 62 / 625,368, each of these US provisional applications shall be incorporated herein by reference in its entirety.

The embodiments and embodiments described herein generally contemplate an anion ion exchange membrane for use in redox flow batteries, more specifically redox flow batteries.

Flow batteries are in the category of electrochemical cells (batteries). In a typical flow battery, chemical energy can be housed in the corresponding chambers and supplied by two liquid electrolytes separated by an ion exchange membrane. Current flow and corresponding ion exchange can occur through the ion exchange membrane while both liquid electrolytes circulate in their chambers. In general, the energy capacity of a flow battery is a function of the amount of liquid electrolyte, and power is a function of the surface area of the electrodes.

The flow battery can operate in two modes. In the first mode, as in the fuel cell, the used electrolyte is extracted and new electrolyte is added to the system. The used electrolyte can be regenerated by a chemical process for further use. In the second mode, a power source can be connected to the flow battery for electrolyte regeneration, similar to the rechargeable battery.

The flow battery is provided according to the first aspect. The flow battery can include at least one rechargeable cell. In some embodiments, the flow battery can include, for example, a plurality of rechargeable cells in a housing. Rechargeable cells generally have an anodic fluid compartment, a cathode fluid compartment, and an ion exchange membrane positioned between the anodic fluid compartment and the cathodic fluid compartment. The additional electrolyte can be stored externally, for example in a tank. This additional electrolyte can be pumped via the anodic or cathodic compartment of the rechargeable cell. In some embodiments, the additional electrolyte can be moved via a gravity feeding system.

According to one aspect, a flow battery is provided. The flow battery can include at least one rechargeable cell. The at least one rechargeable cell may have an anodic fluid compartment, a cathode fluid compartment, and an anion exchange membrane positioned between the anodic fluid compartment and the cathodic fluid compartment. it can. The anode fluid compartment may be configured to hold a first electrolyte having a first cation species. The cathode fluid compartment may be configured to hold a second electrolyte having a second cation species. The anion exchange membrane may be configured to exhibit ionic conductivity between the first electrolytic solution and the second electrolytic solution. The anion exchange membrane shall have a thickness of less than 100 μm and a steady diffusion rate of less than ^{0.4 ppm / hour / cm 2 with} respect to at least one of the first cation species and the second cation species. Can be done.

In some embodiments, at least one of the first cation species and the second cation species can be a metal ion. At least one of the first cation species and the second cation species can be selected from zinc, copper, cerium, and vanadium.

The anion exchange membrane can have a useful life of at least about 12 weeks, which is determined when the internal potential drop is at least about 2.5 V.

The anion exchange membrane can have a thickness of at least less than about 55 μm. In some embodiments, the anion exchange membrane can have a thickness between at least about 15 μm and about 35 μm. For example, the anion exchange membrane can have a thickness of about 25 μm.

In some embodiments, the anion exchange membrane has a steady diffusion rate of less than ^{0.12 ppm / hour / cm 2 with} respect to at least one of the first cation species and the second cation species. Can be done.

The anion-exchange membrane, when measured at direct current after yielded equilibrium 0.5M NaCl solution at 25 ° C., the resistance between about 3.0Ω · cm ² ~ about 10.0Ω · cm ² Can have. The anion-exchange membrane, when measured at direct current after yielded equilibrium 0.5M NaCl solution at 25 ° C., the resistance between about 5.0 ohm · cm ² ~ about 8.0Ω · cm ² Can have. In some embodiments, the anion exchange membrane can have a coion transport rate of at least about 0.95 for at least one non-redox species.

The flow battery can coexist with a high voltage direct current (HVDC) transmission line and can be configured to supply a voltage between about 1000V and about 800KV.

The flow battery can coexist with an automobile and can be configured to supply a voltage between about 100V and about 500V.

According to another aspect, a method for facilitating the use of the flow battery is provided. The method of the present invention can include a step of preparing at least one anion exchange membrane and a step of instructing each anion exchange membrane to be installed in the rechargeable cell of the flow battery. .. The anion exchange membrane has a thickness of less than 100 μm and a steady diffusion rate of less than ^{0.4 ppm / hour / cm 2 with} respect to at least one of the first metal cation species and the second metal cation species. Can be done. Each anion exchange membrane can be installed between the anode fluid compartment and the cathode fluid compartment.

According to some embodiments, the step of preparing the anion exchange membrane can include the step of preparing an anion exchange membrane having a thickness between about 15 μm and about 35 μm.

According to some embodiments, the step of preparing the anion exchange membrane is less than ^{0.12 ppm / hour / cm 2} for at least one of the first metal cation species and the second metal cation species. The first metal cation species and the second metal cation species have an anion exchange membrane that is independently selected from zinc, copper, cerium, and vanadium. It can include steps to prepare.

The method of the present invention can further include a step of charging the flow battery and instructing the flow battery to operate continuously.

According to another aspect, a method for facilitating charge storage is provided. The method of the present invention can include a step of preparing a flow battery and a step of instructing the flow battery to be charged. The flow battery can have a plurality of rechargeable cells. Each rechargeable cell can have an anode fluid compartment, a cathode fluid compartment, and an anion exchange membrane positioned between the anode fluid compartment and the cathode fluid compartment. The anode fluid compartment may be configured to hold a first electrolyte having a first cation species. The cathode fluid compartment may be configured to hold a second electrolyte having a second cation species. The anion exchange membrane may be configured to exhibit ionic conductivity between the first electrolytic solution and the second electrolytic solution. The anion exchange membrane shall have a thickness of less than 100 μm and a steady diffusion rate of less than ^{0.4 ppm / hour / cm 2 with} respect to at least one of the first cation species and the second cation species. Can be done.

The method of the present invention can further include a step of instructing the flow battery to be charged by electrically connecting the flow battery to a variable energy source.

The method of the present invention can further include a step of instructing the flow battery to be electrically connected to a high voltage current (HVDC) transmission line.

In some embodiments, the method of the present invention may further comprise a step of instructing the flow battery to replace at least one of the first electrolyte and the second electrolyte after the flow battery has been discharged. ..

According to another aspect, a method for producing an anion exchange membrane is provided. The method of the present invention comprises a step of integrating a cationic functional monomer having a crosslinking group into a polymerization product and a step of coating a microporous substrate having a thickness of less than about 100 μm with the polymerization product. Be prepared. In some embodiments, the polymerization product can be largely free of cross-linking agents.

According to some embodiments, the microporous substrate can have a thickness of about 25 μm. The microporous substrate can have at least one of polypropylene, high molecular weight polyethylene, ultra high molecular weight polyethylene, polyvinyl chloride, polyvinylidene chloride, polysulfone, and combinations thereof. The microporous substrate can have a porosity between about 25% and 45% and an average pore diameter between about 50 nm and about 10 μm. The microporous substrate can be made of ultra-high molecular weight polyethylene having a porosity of about 35% and an average pore diameter of about 200 nm.

The present disclosure includes all combinations of any one or more of the embodiments and / or embodiments described above, as well as any one or more of the embodiments described in the detailed description and optional examples. Assuming a combination of.

The attached drawings are not intended to be drawn to scale. In the drawings, the same or nearly identical components shown in the various figures are designated by similar reference numerals. For clarity, not all components may be referenced in all drawings.

It is the schematic of the rechargeable flow cell by one Embodiment. It is the schematic of the flow battery by one Embodiment. It is the schematic of the zinc-copper redox flow battery by one Embodiment. It is the schematic of the thin film production line by one Embodiment. It is a copper diffusion graph with respect to the time of some sample ion exchange membranes by one embodiment.

FIG. 1 is a schematic view of an exemplary rechargeable flow cell. This exemplary rechargeable flow cell 100 can have an anode fluid compartment 120 and a cathode fluid compartment 122. The anode fluid compartment 120 and the cathode fluid compartment 122 can be separated by an ion exchange membrane 110. The arrow indicates the direction of the electrolyte flow through the flow cell 100. The flow cell 100 can further have electrodes 160, 162. In some embodiments, the flow cell 100 can have a bipolar electrode that is positioned between the adjacent anode fluid compartment 120 and the cathode fluid compartment 122.

FIG. 2 is a schematic view of an exemplary flow battery 150 including a rechargeable flow cell 100. Although FIG. 2 shows only one rechargeable flow cell 100, it should be understood that, in general, multiple flow cells 100 can be provided within the flow battery 150. The anode liquid compartment 120 and the cathode liquid compartment 122 of the flow cell 100 can be fluidly connected to the external anode liquid tank 130 and the cathode liquid tank 132, respectively. The flow battery 150 can include pumps 140 and 142 for circulating the electrolytic solution. The flow battery 150 can be electrically connected to the charging source 152.

Redox flow batteries (RFBs) operate by storing energy in two different electrolytes, which are often practically aqueous. The amount of energy stored can depend on the amount of the two electrolytes. The RFB can be designed to store the amount of specific energy by selecting the amount of electrolyte. Such techniques can be useful for storing energy from renewable sources that operate intermittently. Another possible use in the RFB is for use in electric vehicles. Their use is to solve one drawback of battery-powered vehicles-the time it takes to recharge the battery-which allows for quick replacement of used electrolytes instead of recharging. Can be done by

A typical recharging process may require several hours to fully charge the battery. In RFB, the electrolyte can be quickly replaced from the vehicle. The discharged electrolyte can be eliminated and replaced with a fully charged electrolyte. Moreover, because the electrolyte is often in liquid form, it may be possible to "refuel" the RFB vehicle in the same amount of time required to refuel the traditional gasoline-powered vehicle. After removing and replacing the electrolyte, the discharged electrolyte can be recharged or regenerated for reuse outside the vehicle at a later time.

For any of the RFB applications described above, ion exchange membranes may be required for electrochemical cells. May be required in some RFB applications. The anion exchange membranes described herein are well suited for RFB applications, but are not limited to a particular type or application of RFB technology.

The RFB applies a redox reaction to charge and discharge the cell. The RFB generally operates with a redox pair (reducing agent and oxidant) that acts as a "rocking chair" in the individual electrode compartment during the charge and discharge cycles of the flow battery. The ion exchange membrane can be positioned to separate the anode solution and the cathode solution. The ion exchange membrane can be selected to prevent energy release due to a chemical reaction between the oxidizing agent and the reducing agent to ensure that electrical energy is delivered to an external load. An exemplary RFB employs zinc and cerium. Examples of charge and discharge electrochemical reactions are described in the following equation:

Charging anode reaction Zn ²⁺ + 2e ← → Zn E ⁰ = -0.763V

Discharge cathode reaction 2Ce ⁴⁺ + 2e ← → ^{2Ce 3+} E ⁰ = -1.44V

Indicated by.

In this exemplary RFB, the total potential of the battery is 2.203 volts. Such RFBs include an anodic solution having zinc ions (Zn ²⁺ ) and a cathode solution having cerium ions (Ce ⁴⁺ ).

Other examples of charge and discharge electrochemical reactions include the following equations:

Discharge cathode reaction Zn ²⁺ + 2e ← → Zn E ⁰ = -0.763V

Charging anode reaction Cu ²⁺ + 2e ← → Cu E ⁰ = -0.340V

Indicated by.

In this exemplary RFB, the total potential of the battery is 1.103 volts. Such RFB comprises a catholyte having a zinc ion ^{(Zn 2+),} and an anolyte having a copper ion ^{(Cu 2+).} FIG. 3 is a schematic view of zinc-copper RFB under charging operating conditions. This exemplary RFB is charged by a DC charging source and also includes a Zn cathode fluid external tank and a copper anode fluid external tank. These tanks are fluidly connected to corresponding compartments located on opposite sides of the anion exchange membrane.

According to some embodiments, the rechargeable cells described herein can include first and second electrolytes. Each of the first and second electrolytic solutions can be provided with a cation. Cations can generally refer to the redox species required for electrode reactions within the flow cell. Each electrolyte can include redox and non-redox species. Therefore, the anode fluid compartment can be configured to hold the first electrolyte having the first cation species, and the cathode fluid compartment can be configured to hold the second electrolyte having the second cation species. can do. In some embodiments, at least one of the cationic species is a metal ion. For example, at least one of the cationic species can be selected from zinc, copper, cerium, and vanadium.

The cation species can be the same or different species. In some non-limiting exemplary embodiments, the rechargeable cell can include zinc-cerium, zinc-copper, zinc-zinc, or vanadium-vanadium. When the same anionic species is adopted for the anode solution and the cathode solution, the anionic species can have different ionic states. For example, zinc flow battery may include a Zn ⁰ or Zn @ 2 ^+. Vanadium flow batteries can include V ²⁺ , V ³⁺ , V ⁴⁺ , and / or V ⁵⁺ . Other anions that can be employed include bromine, nickel, iron, and cyanides (eg, ferricyanides).

The exemplary zinc-cerium RFBs described above generally allow anions to move from the anodic compartment to the anodic compartment during discharge and also allow anions to move from the anodic compartment to the anodic compartment during charging. It can have an anion exchange membrane that allows it to be moved into the chamber. According to some embodiments, the rechargeable cells described herein can have an anion exchange membrane positioned between the anodic and cathodic compartments. This anion exchange membrane can have ionic conductivity between the electrolytes. In general, anion exchange membranes can have ionic conductivity between ions that are not involved in the electrode reaction.

Anion exchange membranes are generally capable of transporting anions under potential differences. The anion exchange membrane can have a fixed positive charge and a movable anion. Ion exchange membrane properties can be controlled by the amount, type, and distribution of fixed ionic groups within the exchange membrane. For example, quaternary and tertiary amine functional groups can give rise to fixed positively charged groups in strong and weak basic anion exchange membranes. Bipolar thin films can have cation exchange membranes and anion exchange membranes laminated or bonded to each other, sometimes with a thin third neutral layer interposed therebetween.

A polymer electrolyte membrane (PEM) is an ion exchange membrane that can function as an electrolyte and as a separator between an anode solution and a cathode solution. Anionic PEMs can include positively charged groups, such as sulfonic acid groups and / or amine groups, that are attached to or as part of the polymer that makes up the PEM. In use, protons, or cations, can generally move through a membrane by transferring from one positive charge fixed to the membrane to another charge that permeates the membrane.

When selecting a membrane, the parameters generally include good chemical, thermal, electrochemical, and mechanical stability. Proper mechanical stability and strength when inflated and under mechanical stress can also be considered. Other parameters may include low resistance, low or unsuitable transportability of electrolyte species, and low cost. The evolution of ion exchange membranes can be a balance of some or all of these properties that overcome competitive effects. The ion exchange membrane can be selected to meet some properties, including: (1) low electrical resistance to reduce potential drop during operation and increase energy efficiency, (2) high co-operation. Ion transport number, (3) high chemical stability including the ability to withstand arbitrary pH and oxidative chemicals ranging from 0 to 14, (4) high withstand the stresses handled during the manufacture of modules or other processing devices. Mechanical strength and (5) good dimensional stability in operation, eg, one with adequate resistance to expansion or contraction when the contact fluid changes concentration or temperature can be selected.

According to some non-limiting embodiments, the anion exchange membrane for RFB minimizes the chemical stability to the battery electrolyte for multiple cycles and the voltage drop during the discharge cycle (including high amperage operation). It can be selected to have high conductivity, prevent coion transport, and have excellent selectivity to maintain high efficiency during the useful life of the RFB.

The inventor generally allows for a thinner membrane to have a lower resistivity and a larger membrane area per unit volume of the device for a given ion exchange membrane. However, thinner membranes can generally be more susceptible to dimensional changes from environmental effects such as changes in the ion concentration or operating temperature of the contact fluid. In general, it can be more difficult to develop and produce thinner films without defects, which means that there is an error margin during production compared to thicker thin films whose thickness can cover the defects that occur during formation. Because it is smaller.

A thin anion exchange membrane with low resistance, low diffusion rate, high coion transport number, and good chemical stability converts a cationic functional monomer having a cross-linking group into a polymer. It can be produced by (polymerization). As described herein, composite ion exchange membranes have been developed, which have microporous thin films saturated with crosslinked polymers with charged ion groups. Anion exchange membranes described herein, of less than 100μm thick, has a resistance of 5.0Ω · ^{cm 2} ~8.0Ω · ^cm 2 in use, and at least with respect to one of the cationic species 0.4 ppm / A steady diffusivity of less than an hour / cm ^{2 can be achieved.} The properties of ion exchange membranes described herein can generally allow the membrane to operate at low resistance without sacrificing membrane integrity. It should be understood that similar methods can be carried out in the production of cation exchange membranes. That is, in this case, the ionic polymer has the relevant functional groups.

WO 2011/025867 (which is incorporated herein by reference in its entirety) includes the step of binding one or more monofunctional ionogenic monomers to at least one polyfunctional crosslinked monomer, and. A method for producing an ion exchange membrane including a step of polymerizing a monomer into the pores of a porous substance is described.

According to one aspect, there is provided a method of producing the ion exchange membrane described herein. The disclosure generally describes the chemicals and materials used to produce exemplary ion exchange membranes. In order to produce a crosslinked film, the micropores of the substrate can be saturated with a polymerized product consisting of crosslinked functional monomers, followed by polymerization (polymerization) of the monomers.

The monomer can have a functional group and a cross-linking group. Here, the term "cross-linking group" can refer to a moiety that has a monomer substituent or a polymerization reaction site and is capable of forming a networked or crosslinked polymer. The term "ionic functional group" can refer to a moiety having a monomeric substituent or a covalently bonded charged group. The charged group can be positively or negatively charged. The monomers described herein can generally have at least one functional group and at least one cross-linking group. According to some embodiments, the molecules described herein can have a hydrocarbon-based structure.

Functional cross-linked monomers can provide stability to the membrane. Membrane stability and relative tightness generally depend on the degree of cross-linking to the same monomer. Stability can further depend on the miscibility between the functional and cross-linking groups. When the two groups are not miscible, a solvent can be added to produce a polymerized solution, typically due to the hydrophobicity and hydrophilicity of the cross-linking and ionic groups, respectively. During the thermal polymerization process, the volatile solvent can evaporate and alter the monomer distribution in solution. The solvent can further change the reactivity of the two groups due to the solvation effect. The result is generally to form a block copolymer instead of producing a uniform monomer distribution.

If the functional monomer itself is not crosslinked, the functional groups may be at risk of leaving the polymer network. When each functional group is crosslinked, only hydrolysis of the ester group reduces the degree of cross-linking, which can reduce the rate of degradation (deterioration) of the membrane. Thus, when obtained with the functionally crosslinked monomers described herein, the monomers can be in a fully crosslinked state and the functional groups can be covalently attached to the polymer backbone of the membrane. Decreasing the degradation rate of the membrane can result in increased chemical stability in the electrolyte solution and significantly increased lifetime. In addition, due to the cross-linking groups, the polymerization product can be almost cross-link free.

In some non-limiting embodiments, the method of the invention polymerizes a step of integrating a cationic functional monomer having a cross-linking group into a polymerization product and a microporous substrate having a thickness of less than about 100 μm. It can have a step of coating with an object. The polymerization product can include a solvent. The polymerization product can include a polymerization initiator.

The functional group can be a positively charged amine group, for example a quaternary ammonium group. The tertiary ammonium group can be quaternized with a quaternary chemical. The quaternary ammonium functional group is basic in strength and can be ionized to act over a pH range of 0-14 to allow a wide operating range.

The cross-linking group can produce a film having a high cross-linking density without adding an external cross-linking agent. The crosslinked monomer can have at least one polymerization reaction site. In some embodiments, the crosslinked monomer can have more than one polymerization reaction site. In some embodiments, the polymer is 100% crosslinked.

The cationic functional monomer can be copolymerized with at least one secondary functional monomer. The secondary functional monomer can be configured or selected to alter the ion exchange capacity without cross-linking. Secondary functional monomers include, but are not limited to, vinyl chloridebenzyltrimethylammonium, trimethylammonium chloride / ethylmethacrylic, methacrylamidepropyltrimethylammonium chloride, (3-acrylamidepropyl) trimethylammonium, 4-vinylpyridine, and one. It can be selected from the group containing or more polymerization initiators.

The cationic functional monomer can be copolymerized with at least one non-functional secondary monomer. This non-functional secondary monomer can be configured or selected to alter the resistivity of the membrane. The non-functional secondary monomer can be configured or selected to alter the miscibility of the monomer and / or the polymerization product. For example, the non-functional monomer can be selected to give rise to the ability to prevent phase separation caused by the hydrophobicity and hydrophilicity of the cross-linking and ionic groups, respectively. In addition, copolymerization with non-functional monomers allows the polymerization products to be kept in a fully mixed state without excess solvent. In some embodiments, the non-functional secondary monomer is, but is not limited to, styrene, vinyltoluene, 4-methylstyrene, t-butylstyrene, α-methylstyrene, anhydrous methacrylic, methacrylic acid, n-vinyl-. 2-Pyrrolidone, Vinyltrimethoxysilane, Vinyltriethoxysilane, Vinyl-tris- (2-methoxyethoxy) silane, Vinylidene chloride, Vinylidene fluoride, Vinylmethyldimethoxysilane, 2,2,2, -Trifluoroethyl methacrylate -It can be selected from the group containing allylamine, vinylpyridine, maleic anhydride, glycidyl methacrylate, hydroxyethyl methacrylate, or ethyl methacrylate.

Crosslinkers can be incorporated in some embodiments and for some envisioned use. Such cross-linking agents include, for example, propylene glycol dimethacrylate, isobutylene glycol dimethacrylate, octa-vinyl POSS®, octa-vinyldimethylsili POSS®, vinyl POSS® mixture, Octa. Vinyl POSS®, Trisilabolethyl POSS®, Trisylanolisooctyl POSS®, Octasilane POSS®, Octahydro POSS®, Epoquicyclohexyl-POSS® Cage Mixture , Glycidyl-POSS® Cage Mixture, Methul-POSS® Cage Mixture, or Acrylo POSS® Cage Mixture, all of which are Hybrid Platics (Hattis, Mississippi, USA). It is distributed by (Burg).

The method of the present invention comprises the step of coating a microporous substrate with a polymerization product. The polymerization product can contain one or more solvents. Solvents that can be incorporated may include 1-propanol and dipropylene glycol. In some embodiments, hydroxyl groups containing solvents such as alcohols (eg, isopropanol, butanol, diols such as various glycols, or polyols such as glycerin) can be incorporated. In addition, aprotic solvents such as N-methylpyrrolidone and dimethylacetamide can be incorporated. These solvents are exemplary and additional or alternative solvents will be apparent to those skilled in the art.

The polymerization products are free radical initiators such as benzoyl peroxide (BPO), ammonium persulfate, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2-methylpropionamidine). Dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2yl) propane], and dimethyl 2,2'- Azobis (2-methylpropionate) can be included.

The microporous substrate can be selected to have adequate mechanical stability, porosity, and thickness. According to some embodiments, the microporous substrate may have a thickness of less than 100 μm, a void (porous) ratio between about 25% and 45%, and an average pore diameter between about 50 nm and about 10 μm. it can. The microporous substrate can have at least one of polypropylene, high molecular weight polyethylene, ultra high molecular weight polyethylene, polyvinyl chloride, polyvinylidene chloride, polysulfone, and combinations thereof. These exemplary materials can generally have high mechanical stability at a thickness of 15 μm or more.

In general, the thickness of the microporous substrate can be as thin as possible while providing adequate mechanical stability for the anion exchange membrane. The thickness of the microporous substrate can be measured without considering the depth of the holes. In some embodiments, the microporous substrate can have a thickness of less than about 155 μm. The microporous substrate can have a thickness of less than about 100 μm. The microporous substrate can have a thickness of less than about 75 μm. The microporous substrate can have a thickness of less than about 55 μm. According to some embodiments, the microporous substrate can have a thickness of about 25 μm. The microporous substrate can have a thickness of about 15 μm, about 20 μm, about 25 μm, about 30 μm, about 35 μm, about 40 μm, or about 45 μm.

Porosity can be selected to maintain proper mechanical stability and allow proper coating on the substrate. Therefore, the porosity can be selected based on the coating composition, substrate material, and / or substrate thickness. Porosity, expressed as a percentage, can refer to the amount of holes in the total volume of the substrate. In some embodiments, the microporous membrane can have a porosity between about 25% and about 45%. The microporous membrane can have a porosity between 20% and 40%. The microporous membrane can have a porosity of about 20%, about 25%, about 30%, about 35%, about 40%, or about 45%. In other embodiments, the porosity can be greater than about 45%. For example, the porosity can be greater than about 60% or greater than 70%. In a non-limiting exemplary embodiment, the substrate material can be ultra high molecular weight polyethylene, the thickness of the substrate can be between about 15 μm and 35 μm, and the porosity can be about 35%. Can be selected to be.

The porosity can be further selected to correspond to the selected average pore size and vice versa. The average pore size can be further selected based on the coating composition and / or substrate material. For example, the average pore size can be selected so that the coating on the substrate can be made almost uniform. The average pore size can be selected to have an additional or alternative effect on membrane performance. The pore size of the membrane can change the resistivity, diffusivity, ion transport rate, and tightness of the membrane structure. Without being bound by any special theory, the selected membrane parameters (especially pore size, degree of cross-linking, ionic functionality, and thickness) all allow membrane performance.

In some embodiments, the average pore size can range from about 50 nm to about 10 μm. The average pore size can range from about 100 nm to about 1.0 μm. The average pore size can range from about 100 nm to about 200 nm. The average pore diameter can be about 100 nm, about 125 nm, about 150 nm, about 175 nm, about 200 nm, about 225 nm, or about 250 nm.

The microporous substrate material can be selected to have adequate mechanical stability at the desired thickness and porosity. In some embodiments, the microporous substrate can have at least one of polypropylene, high molecular weight polyethylene, ultra high molecular weight polyethylene, polyvinyl chloride, polyvinylidene chloride, polysulfone, and combinations thereof. These exemplary materials can generally have high mechanical stability at a thickness of 15 μm or more. Additionally, the exemplary material can have mechanical stability at such a thickness and with a porosity of up to 70%.

The method of the present invention can further include a step of heating the coated microporous substrate or a step of performing the coating step at an elevated temperature. For example, substrate hole filling or saturation can be performed above about 40 ° C. or at about 40 ° C. to reduce air solubility. In some embodiments, the substrate can be coated by immersing it in a polymerization solution under vacuum treatment, after which a heating step is performed.

The method of the present invention comprises a step of removing air bubbles after coating the microporous substrate. In some embodiments, the substrate sample is pre-immersed and treated to remove air bubbles, eg, this is to place the sample on a polyester or similar sheet, cover it with a cover sheet, and remove air bubbles. It can be done by smoothing. This process can be performed within a single sheet or sheet assembly.

Polymerization can be carried out in the heating unit or on the heated surface. The coated substrate can be placed on the heated surface at a temperature and time sufficient to initiate and complete the polymerization. Sufficient time and temperature can generally depend on the composition of the polymerization product. The polymerization reaction can employ, for example, treatment with ultraviolet rays or ionizing radiation (such as gamma radiation or electron beam radiation).

According to some embodiments, the methods described herein can significantly reduce production time, for example by requiring only one coating step. The production time can be shortened by not additionally incorporating a cross-linking agent. Subsequent cross-linking steps can be avoided. Further, the produced anion exchange membrane has a thickness as small as 25 μm or 15 μm, and can maintain the desired mechanical strength and chemical stability during use.

The membrane can be produced on a production line as shown in FIG. The exemplary production line 200 of FIG. 4 has a solution tank 210 for coating the membrane substrate. This exemplary production line 200 can move the coated substrate along the heating zone 220 on the mechanical moving element 230. The mechanical moving element can optionally be a conveyor belt 230 having a motor 232. The motor can operate to control the speed along the heating zone 220 (as described in more detail in the examples). The heating zone 220 can include a plurality of heating blocks 221 and 222, block 223, and block 224. Here, the exemplary heating zone 220 has four heating blocks (heating zones), while the heating zone 220 can have more or fewer heating blocks. The number of heating blocks can affect the operating speed of the mechanical moving element 230. The production line 200 can further include rollers 240 for removing air bubbles. In other embodiments, the heating zone 220 can be a light initiator rather than a thermal initiator (starter). In some embodiments, the heating zone 220 can have an ultraviolet radiation zone.

In general, the thickness of the ion exchange membrane can allow lower internal resistance and / or higher power output. The thickness of the anion exchange membrane may depend on the thickness of the microporous substrate. Therefore, the anion exchange membrane can have a thickness of less than about 155 μm. The anion exchange membrane can have a thickness of less than about 100 μm. The anion exchange membrane can have a thickness of less than about 75 μm. The anion exchange membrane can have a thickness of less than about 55 μm. The anion exchange membrane can have a thickness of about 15 μm, about 20 μm, about 25 μm, about 30 μm, about 35 μm, about 40 μm, and about 45 μm.

In some embodiments, the anion exchange membrane can have a thickness between about 15 μm and about 100 μm. The anion exchange membrane can have a thickness between about 15 μm and about 75 μm. The anion exchange membrane can have a thickness between about 15 μm and about 50 μm. The anion exchange membrane can have a thickness between about 15 μm and about 35 μm. The anion exchange membrane can have a thickness between about 15 μm and about 25 μm.

The ion exchange membranes described herein provide excellent diffusivity as compared to conventional membranes of similar thickness. In general, diffusivity can mean the number of ions across a unit area of an ion exchange membrane over a predetermined time. Therefore, the diffusivity of the membrane can be driven by the species concentration difference across the membrane. The stationary diffusivity can mean a diffusivity in which the ion flux is substantially constant over time. As described herein, the steady diffusivity is measured for at least one cation species. In addition, steady diffusivity values _{measure membrane samples between 0.4 M CuSO 4} solution and 0.5 M NaCl solution at 25 ° C. and monitor ^{Cu 2+ in a room with 0.5 M NaCl solution.} Can be determined by doing.

In some embodiments, the anion exchange membrane can have a steady diffusion rate of less than ^{0.4 ppm / hour / cm 2 for at least one cation species.} In some embodiments, the anion exchange membrane can have a steady diffusion rate of less than ^{0.4 ppm / hour / cm 2 for both cationic species.} Anion exchange membrane is less than 0.3 ppm / hr / cm ^2, less than 0.2 ppm / hr / cm ^2, less than 0.15 ppm / hr / cm ^2, 0.12 ppm / hr / cm of less than ^2, 0.1 ppm / It can have a steady diffusion rate of less than hour / cm ^2, less than 0.08 ppm / hour / cm ^2, less than 0.05 ppm / hour / cm ^{2, and} less than 0.03 ppm / hour / cm ^2. Therefore, the above-mentioned constant diffusivity values _{test the membrane between 0.4 M CuSO 4} ^{solution and 0.5 M NaCl solution at 25 ° C. and also Cu 2+} in a separable chamber of 0.5 M NaCl solution. Is accurate when monitoring.

The lower electrical resistance of the membrane can reduce the electrical energy required for operation. Membrane resistivity is generally reported in ohms and length (Ωcm). However, the resistance may not be evenly distributed along the membrane area. Area film resistance is measured in ohms and area (Ωcm ^2). Area membrane resistance can be measured by comparing the electrolyte resistance of a flow cell with an ion exchange membrane to that of a flow cell without an ion exchange membrane. For example, a cell having two electrodes of known area in an electrolyte solution (generally platinum or graphite can be used) can be set up. One cell can have an ion exchange membrane sample of known area between the electrodes. Position the electrodes so that they do not come into contact with the membrane. The membrane resistance can be estimated by subtracting the membraneless electrolyte resistance from the electrolyte resistance having the membrane in place.

Ion exchange membrane resistance can also be measured by determining the voltage vs. current curve within a cell that has two well-stirred chambers separated by the membrane. The mercuric chloride electrode can be positioned to measure the potential drop across the membrane. The gradient of the voltage drop can be plotted against the current curve, which is obtained by varying the voltage and measuring the current.

In addition, electrochemical impedance can be used to measure ion exchange membrane resistance. In this method, alternating current can be applied to the membrane. Measurements at a single frequency generally provide data related to the electrochemical properties of the membrane. Detailed structural information can be obtained by using frequency and amplitude variations.

^{In some embodiments, the anion exchange membrane is approximately 3.0 Ω · cm 2} to about 10.0 Ω · cm as measured by direct current after equilibration with a 0.5 M NaCl solution at 25 ° C. It can have a resistance between ^two. Anion exchange membrane, when measured at direct current after yielded equilibrium 0.5M NaCl solution at 25 ° C., has a resistance between about 5.0 ohm · cm ² ~ about 8.0Ω · cm ² be able to. Anion exchange membrane, when measured at direct current after yielded equilibrium 0.5M NaCl solution at 25 ° C., has a resistance between about 6.0Ω · cm ² ~ about 7.0Ω · cm ² be able to. The resistance can be chosen to be as low as possible and to be determined by other parameters of the membrane (eg, material, thickness, etc.). In some embodiments, ion exchange membranes produced almost without crosslinkers as described herein can have lower resistance than ion exchange membranes produced with crosslinkers. Anion exchange membrane, when measured at direct current after yielded equilibrium 0.5M NaCl solution at 25 ° C., about 3.0Ω · cm ^2, from about 4.0Ω · cm ^2, from about 5.0 ohm · cm ^2, about 5.5Ω · cm ^2, about 6.0Ω · cm ^2, about 6.5Ω · cm ^2, about 7.0Ω · cm ^2, about 7.5Ω · cm ^2, about 8.0Ω · cm ² , Approximately 9.0 Ω · cm ² , can have a resistance of approximately 10.0 Ω · cm ^2.

The coion transport rate generally means the relative transport of counterions to coions during use of a flow battery. An ideal cation exchange membrane allows only positively charged ions to pass through the membrane, resulting in a coion transport number of 1.0. The cation transport number of the membrane can be determined by measuring the potential across the membrane with the membrane separating monovalent salt solutions of different concentrations. The methods and calculations used herein will be described in more detail in the Examples section.

In some embodiments, the anion exchange membrane can have a coion transport rate of at least about 0.95 for at least one non-redox species. The non-redox species can be any non-redox species of electrolyte. Anion exchange membranes can have a coion transport rate of at least about 0.95 for all non-redox species. The anion exchange membrane is at least about 0.9, at least about 0.91, at least about 0.92, at least about 0.93, at least about 0.94, at least about 0.95, at least about 0.96, at least about. It can have a coion transport number of 0.97, at least about 0.98, and at least about 0.99.

The flow cell can further include at least one electrode. The power of the flow cell can be a function of the surface area of the electrodes. One electrode can be a bipolar electrode positioned to allow fluid communication with the first and second electrolytes. The bipolar electrode can be positioned between the first electrolytic solution and the second electrolytic solution. The electrodes described herein can be composed of corrosion resistant conductive materials selected to have suitable electrical, chemical and mechanical stability for use. The bipolar electrode may have a conductive material or a layer of conductive material. In some embodiments, the bipolar electrode can have zinc.

The flow cell can have a first electrode and a second electrode, one of which is positioned within each cell half. The first electrode can be positioned in the cell half containing the first electrolytic solution, and the second electrode can be positioned in the cell half containing the second electrolytic solution. The electrode can have one or more layers of conductive material or conductive material. In some embodiments, the electrodes can have platinum or graphite. The flow cell can have at least one separator configured to keep the ion exchange membrane and the electrodes out of contact with each other.

The flow battery includes a plurality of flow cells. In some embodiments, the flow battery can include an external electrolyte tank. The flow battery can be configured to feed the electrolyte from the tank and allow it to pass through the cell so as to contact the ion exchange membrane and / or the electrode. The flow battery can include one or more pumps configured to circulate the electrolyte through the cell. Flow cells can be fluidly connected to each other. In some embodiments, the flow cells do not fluidly connect to each other.

According to another aspect, a method for facilitating the use of the flow battery is provided. The method of the present invention may include a step of preparing at least one ion exchange membrane as described herein and a step of instructing the installation of the ion exchange membrane in the rechargeable cell of the flow battery. it can. The ion exchange membrane can be an anion exchange membrane. In general, the ion exchange membrane can be placed between the anodic and cathodic compartments of the rechargeable cell. The method of the present invention further comprises a step of charging the flow battery and instructing the flow battery to operate continuously.

In some embodiments, the flow battery can operate with a life of at least about 6 weeks before the electrolyte needs to be replaced or recharged. Flow batteries can operate with a life of at least about 12 weeks. In some embodiments, the ion exchange membrane can have a useful lifespan of about 6 weeks, about 8 weeks, about 10 weeks, about 12 weeks, about 14 weeks, or about 16 weeks. In some embodiments, the ion exchange membrane can have a useful life of up to about 20 weeks. The useful life of the membrane can be translated into the number of cycles in which the membrane can operate before the electrolyte needs to be replaced. In some embodiments, the ion exchange membrane can operate for more than 4000 cycles. For example, the ion exchange membrane can operate for about 4500 cycles, about 5000 cycles, about 5500 cycles, about 6000 cycles, about 6500 cycles, or about 7000 cycles.

As described herein, useful life can mean the life of a flow battery or ion exchange membrane in continuous use before the electrolyte requires replacement or recharging. In a non-limiting exemplary embodiment, when Cu2 ⁺ diffuses into the Zn2 ⁺ compartment (or conversely Zn2 ⁺ diffuses into the Cu2 ⁺ compartment), Cu2 ⁺ is associated with the Zn metal formed during discharge. Can react. This reaction can ^{convert Cu 2+} to Cu ⁰ to reduce the conductivity or increase the voltage at a constant current. The voltage can be a good indicator of the amount of ^{Cu2 +} diffused through the membrane. Therefore, the useful life of the ion exchange membrane may reach the threshold when the internal potential drop is high and the output is low, indicating that the electrolyte needs to be replaced or recharged. In some embodiments, it is possible that the useful lifetime threshold of the ion exchange membrane is reached when the internal potential drop is between about 2.0 and about 3.0 volts. It is possible that the useful lifetime of the ion exchange membrane threshold has been reached when the internal potential drop is at least about 2.5 volts. The flow battery described herein can include a sensor that determines the internal potential drop and optionally a user interface that indicates when the internal potential drop reaches the useful life threshold.

The useful life of the ion exchange membrane may depend on the usage of the membrane. For example, the useful life can vary depending on the choice of electrolyte or electrode material. The useful life of the ion exchange membrane can vary depending on the size of the rechargeable cell, electrode, and / or electrolyte compartment. The useful life of the ion exchange membrane can also vary depending on the material selected. For example, the useful life can vary depending on the coating material, the substrate material, and whether the substrate is coated with a cross-linking agent. In general, ion exchange membranes can have a useful life of about 6 to about 16 weeks. The method of the present invention can further include a step of instructing to determine the useful life of the ion exchange membrane and a step of optionally instructing the electrolyte to be replaced after exhaustion of the electrolyte. .. In some embodiments, the method of the invention can comprise the step of replacing the ion exchange membrane after exhaustion of the ion exchange membrane.

According to some embodiments, the flow battery can be configured to co-exist with a high voltage direct current (HVDC) transmission line. Flow batteries can operate to store electrical energy for use on HVDC transmission lines. In general, such flow batteries can supply voltages between about 1000V and about 800KV.

According to some embodiments, the flow battery can be configured to be coexistent with the vehicle. Flow batteries can operate to store electrical energy for use in automobiles. Such a flow battery can supply a voltage between about 100V and about 500V corresponding to a conventional automobile battery.

According to another aspect, the present invention provides a method of facilitating storage of charges. This method includes a step of preparing a flow battery as described in the present specification and a step of instructing the flow battery to be charged. Flow batteries can be charged by connecting to an energy source. In some embodiments, the flow battery can be charged by connecting to a variable energy source. The variable energy source can be any energy source that cannot be transported due to its fluctuating nature. Examples of variable energy sources can be photovoltaic systems, wind power systems, and hydropower systems such as wave and tidal power. Other variable energy sources will be readily apparent to those skilled in the art. In general, variable energy sources can include sources that require high energy storage to provide continuous operation. Therefore, the method of the present invention can further include a step of instructing the flow battery to be charged by electrically connecting the flow battery to an energy source, for example, a variable energy source.

The method of the present invention can further include instructing the flow battery to be electrically connected to an energy transmission line or to a point of use, eg, a customer. The flow battery can be electrically connected to the HVDC transmission line. HVDC transmission lines can be used for long-distance transmission. The HVDC transmission line can also be electrically connected to a regional distribution system, eg, an alternating current (AC) regional distribution system.

In some embodiments, the method of the invention can comprise a step of instructing the flow battery to be recharged after discharge. The flow battery can be discharged and recharged after the useful life of the ion exchange membrane has been used. In another embodiment, the method of the present invention can further include a step of instructing to replace at least one of the first electrolyte and the second electrolyte after the flow battery is discharged. The electrolyte can be extracted as a used electrolyte and replaced with a new electrolyte for quick charging. The used electrolyte can be recharged for further use.

The features and advantages of these and other embodiments will be better understood from the examples below. These examples are intended to be descriptive in nature and should not be considered to limit the scope of the invention. In the following examples, ion exchange membranes of the desired quality are produced by coating a microporous substrate with a polymerization product.

Example 1: Preparation of test samples Laboratory studies were conducted to design the preparation and use of ion exchange membranes. This laboratory study included the steps of making small membrane coupons (cutting specimens) and performing resistivity tests and coion transport tests on these coupons.

The porous membrane substrate was die-cut to form a coupon having a diameter of 43 mm. Larger discs (50 mm and 100 mm diameter) of clear polyester sheet were also die cut. A 105 mm aluminum weighing pan was used to hold the set of coupons. The coupon was sandwiched between two polyester membrane discs.

First, the substrate coupon was completely wetted with a monomer solution to prepare a test sample. For this wetting, the preparation solution was added to an aluminum saucer and a polyester film disc with the substrate coupon was immersed in the solution with the substrate coupon to finally saturate the porous support. The saturated support was removed from the monomer solution and placed on a piece of polyester membrane. Bubbles were removed from the coupon by smoothing or squeezing the coupon. Bubbles can be eliminated with a convenient tool such as a small glass rod or by hand.

The second polyester disc was laminated onto the first coupon and smoothed to provide perfect surface contact between the coupon and the lower and upper polyester film layers. The second porous substrate was laminated on the upper polyester membrane, and the preceding steps (saturation, smoothing, and addition of the polyester membrane cover layer) were repeated to create a multi-layer sandwich of two coupons and two polyester membrane layers. ..

A typical experimental trial had a multi-layer sandwich of 10 or more saturated substrate coupon layers. The rim of the aluminum pan can be crimped downward to hold the disc / coupon assembly if desired.

The saucer and assembly were then placed in a sealable bag. Here, they were placed in a ziplock polyethylene bag. The bag was sealed after the addition of an inert gas, here a low positive pressure of nitrogen. A bag containing the saucer and coupon assembly was placed in an oven at 80 ° C. for about 60 minutes. The bag was then removed and cooled. The reacted ion exchange membrane coupon was then placed in a 0.5 M NaCl solution at 40 ° C. to 50 ° C. for at least 30 minutes and soaked in the NaCl solution for as long as 18 hours.

Therefore, laboratory membrane coupons are suitable for ion exchange membrane testing.

Example 2: Preparation of Ion Exchange Membrane with UHMWPE Samples were prepared to determine the suitability of ultra high molecular weight polyethylene (UHMWPE) as the membrane substrate material.

The monomer mixture was incorporated into a polymerization product with a solvent as described herein. A 25 μm thick porous film made from UHMWPE with a porosity of at least 35% and a pore size between 50 nm and 10 μm was saturated in the polymerization product for about 30-60 seconds. Saturated films were placed between Mylar® sheets (DuPont Teijin Films, Chesterfield, Virginia) to prevent oxygen ingress. The Mylar® sheet was clamped in place and the film was heated to 80 ° C. for 30 minutes.

The permeability test was performed by placing a membrane in the test cell. A 0.5 M solution of CuSO ⁴ was added to one side of the membrane and a 0.5 M solution of NaCl was added to the other side of the membrane. The membrane was sealed in the test cell using a gasket. After 4 weeks, the NaCl solution lacked detectable CuSO ⁴ and showed a non-permeable membrane. The resistivity was measured to be between 5.0 and 8.0 Ω · cm ² , and the coion transport number was measured to be 0.95.

Therefore, membranes with UHMWPE microporous substrates exhibit impermeable, suitable resistivity and high coion transport rates.

Example 3: Preparation of Ion Exchange Membrane with Polyethylene Samples were prepared to determine the suitability of polyethylene as the membrane substrate material.

The monomer mixture was incorporated into a polymerization product with a solvent as described herein. A 25 μm-thick porous film (membrane) obtained from Entec International (Newcastle upon Tyne, UK) was used as the porous substrate. The porous film had a porosity of about 35% and a pore size of about 200 nm (as an average value reported by the distributor). The porous film was saturated in the polymerization product for about 30-60 seconds. Saturated films were placed between Mylar® sheets to prevent oxygen ingress. The Mylar® sheet was clamped in place and the film was heated to 80 ° C. for 30 minutes.

The resistivity and conion transport rate were measured in the same manner as in Example 2. The resistivity was measured to be between 5.0 and 8.0 Ω · cm ² , and the coion transport number was measured to be 0.95.

Therefore, a membrane having a polyethylene microporous substrate exhibits a suitable resistivity and a high coion transport number.

Example 4: Constant Diffusivity and Resistance of the Illustrative Membrane The ion exchange membrane prepared as described in Example 2 was tested for the diffusivity to ^{Cu 2+ ions.} The membrane was placed between the chambers in a two-chamber test cell. The active area of the diffuse flux was about 4.5 cm ² . On the other hand, the chamber contained about 100 mL ^{of 0.4 M CuSO 4.} The other chamber contained approximately 100 mL of 0.5 M NaCl. The ^{chamber containing CuSO 4} was slowly stirred by a magnetic stirring bar.

The 0.5 M NaCl solution was sampled by UV spectroscopy. The concentration of Cu ²⁺ was determined by absorbing the solution with a quartz cuvette with a 10 mm optical path length. The instrument was "zeroed" by air as an absorption medium. The cuvette was filled with 0.5 M pure NaCl and absorption was recorded as background absorption at a wavelength near 246 nm. 0.5 M NaCl containing diffused Cu ²⁺ was measured by absorption at a wavelength of 246 nm. After absorption of pure NaCl, Cu concentration (ppm) was obtained using the standard curve calculated according to the procedure described above.

Table 1 presents several membranes prepared using the method described in Example 2, where the reference sample is an AMX membrane (distributed by Astom in Tokyo, Japan). References 1 to 4 have slight variations in the polymerization product coated on the substrate.

As shown in Table 1 below, the test films 1 to 4 have a higher resistivity than the reference film, but the test films 1 to 3 have a considerably lower diffusivity than the reference film. Further, the test films 1 to 4 have a thickness smaller than that of the reference film.

Therefore, the test films 1 to 4 are superior to the reference film in terms of thickness and diffusivity. Test films 1 to 4 provide a more suitable resistivity.

Example 5: Effect of cross-linking agent on resistance and steady diffusivity An ion exchange membrane was prepared as described in Example 2. The resistance of the film was ^{6.44 Ω · cm 2} tested as described in Example 2.

The polymerization product was changed to change its concentration by adding ethylene glycol dimethacrylate (EGDM). EGDM is an acrylate-based crosslinker. The addition of EGDM shows significant changes in membrane resistance and diffusivity, as shown in Table 2. EGDM reduces diffusivity but significantly increases resistance.

Therefore, the addition of a cross-linking agent can generally reduce the diffusivity of the membrane. However, cross-linking agents tend to increase resistivity to an inoperable degree in some cases.

Example 6: Production of Ion Exchange Membrane A polymerization product was prepared as described in Example 2. The polymerization product was added to the laboratory scale production line. The porous substrate was moved through a polymerization product solution tank and sandwiched between engaging roller pairs. A saturated porous film was sandwiched using a two-layer Mylar® sheet. The membrane was moved into a heating zone with a total length of 3.6576 m (12 ft). The heating zones were heating blocks that were controlled independently of each other and contained four heating blocks, each having a length of 0.9144 m (3 ft). The membrane production line was operated under movement speed control in order to have the ability to change the heating time.

Table 3 presents the membrane properties for varying heating times. All four zones were assumed to have a controlled temperature of 120 ° C.

Therefore, the membrane produced by the production line can exhibit a suitable resistivity and a high coion transport number.

Example 7: Useful life of the ion exchange membrane The ion exchange membrane prepared as described in Example 2 was tested for the dispersion rate with respect ^{to the expanded Cu 2+ ions over time through the membrane.} Test films 1 to 5 were compared with reference film AMX (distributed by Astom in Tokyo, Japan). FIG. 5 is a graph of the diffused copper concentration of the test films 1 to 5 and the reference film over a period of up to about 190 hours.

The initial output (power) of the test film was potentially slightly lower than the reference film due to the higher resistance in the test film (see, eg, Table 2). The test membrane initially showed a greater internal potential drop (volt), but lasted about 6000 cycles before reaching the 2.5 V internal potential drop threshold. The reference membrane lasted about 4000 cycles before reaching the internal potential drop threshold of 2.5 V.

Considering the linear approximation and the test concentration (0.4M CuSO ⁴ ), which is about half of the working concentration, it can be expected that the useful life of the test membrane can be longer than 12 weeks. The useful life of the test membrane can be about 13-14 weeks. It is considered that the useful life of the test membrane will be increased by further experiments.

The examples show that an ion exchange membrane can be produced with excellent properties and usefulness in flow battery applications. It is conceivable that the examples can further change the membrane properties based on the changes in the chemical properties.

The wording and terminology used herein are for explanatory purposes only and should not be construed as limiting. As used herein, the term "plurality" means two or more matters or components. The terms "comprising", "including", "carrying", "having", "containing", and "Involving" is not limited in any of the stated specification, claims, etc., i.e., "including but not limited." to) "means. Therefore, the use of these terms is meant to include the matters presented thereafter, their equivalents, and any additional matters. Only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed terms in terms of claims, respectively. An ordinal term such as "first", "second", "third", etc. in the claims that modifies the claim element is itself one. There is a given name to distinguish the claims element, which does not imply any priority, precedence or order over the other elements of the claim element, or a temporary order in which the act of the method is performed. It is used only as a marker that distinguishes one claim element from another element that has the same name (but uses ordinal terms).

Although some aspects of at least one embodiment have been described, of course, various modifications, changes and improvements will be readily recalled to those skilled in the art. Any feature described in any embodiment may be included or replaced with any feature in any other embodiment. Such modifications, changes and improvements are intended to be part of this disclosure and within the scope of the present invention. Therefore, the above description and drawings are merely examples.

Those skilled in the art will appreciate that the parameters and configurations described herein are exemplary and that the actual parameters and / or configurations are based on the particular application in which the disclosed methods and materials are used. You can do it. Those skilled in the art will also be able to recognize or confirm the equivalent of the particular embodiments disclosed using mere conventional experiments.

Claims (26)

A flow battery comprising at least one rechargeable cell, wherein the rechargeable cell is:
An anodic solution compartment configured to hold a first electrolyte with a first cation species, and
A cathode liquid compartment configured to hold a second electrolyte having a second cation species, and the first electrolyte and said, positioned between the anode fluid compartment and the cathode fluid compartment. An anion exchange film configured to exhibit ionic conductivity with a second electrolytic solution, having a thickness of less than 100 μm, and at least one of the first cation species and the second cation species. A flow battery comprising the anion exchange membrane having a steady diffusion rate of less than 0.4 ppm / hour / cm ^2. The flow battery according to claim 1, wherein at least one of the first cation species and the second cation species is a metal ion. The flow battery according to claim 2, wherein at least one of the first cation species and the second cation species is selected from zinc, copper, cerium, and vanadium. In the flow battery according to claim 3, the anion exchange membrane has a useful life of at least about 12 weeks, which is determined when the internal potential drop is at least about 2.5 V. The flow battery according to claim 1, wherein the anion exchange membrane has a thickness of at least about 55 μm. The flow battery according to claim 5, wherein the anion exchange membrane has a thickness of at least between about 15 μm and about 35 μm. The flow battery according to claim 6, wherein the anion exchange membrane has a thickness of about 25 μm. In the flow battery according to claim 7, the anion exchange membrane has a steady diffusion rate of less than ^{0.12 ppm / hour / cm 2 with} respect to at least one of the first cation species and the second cation species. Have a flow battery. In the flow battery according to claim 1, the anion exchange membrane is measured with a direct current after an equilibrium state is formed in a 0.5 M NaCl solution at 25 ° C., and the anion exchange membrane is about 3.0 Ω · cm ² to about 10. A flow battery having a resistance between 0 Ω and cm ^2. In the flow battery according to claim 9, the anion exchange membrane has a DC current of about 5.0 Ω · cm ² to about 8. when measured by a direct current after an equilibrium state is formed in a 0.5 M NaCl solution at 25 ° C. A flow battery having a resistance between 0 Ω and cm ^2. The flow battery according to claim 10, wherein the anion exchange membrane has a coion transport number of at least about 0.95 for at least one non-redox species. The flow battery according to claim 1, wherein the flow battery is configured to be coexistent with a high voltage direct current (HVDC) transmission line and to supply a voltage between about 1000 V and about 800 KV. The flow battery according to claim 1, which is configured to be coexistent with an automobile and to supply a voltage between about 100 V and about 500 V. In a way to facilitate the use of flow batteries
At least one anion exchange membrane having ^{a thickness of less than 100 μm and a constant diffusivity of less than 0.4 ppm / hour / cm 2} for at least one of the first metal cation species and the second metal cation species. A method comprising a step of preparation and a step of instructing each anion exchange membrane to be placed between the anode fluid compartment and the cathode fluid compartment in the rechargeable cell of the flow battery. In the method of claim 14, the step of preparing the anion exchange membrane comprises the step of preparing an anion exchange membrane having a thickness between about 15 μm and about 35 μm. In the method of claim 15, the step of preparing the anion exchange membrane is less than ^{0.12 ppm / hour / cm 2} for at least one of the first metal cation species and the second metal cation species. The first metal cation species and the second metal cation species have an anion exchange membrane that is independently selected from zinc, copper, cerium, and vanadium. A method that includes steps to prepare. The method according to claim 16, further comprising a step of charging the flow battery and instructing the flow battery to operate continuously. In a way that facilitates the storage of electric charge
Each rechargeable cell comprises a step of preparing a flow battery with multiple rechargeable cells.
Anode fluid compartment configured to hold the first electrolyte with the first cation species,
A cathode liquid compartment configured to hold a second electrolytic solution having a second cation species, and the first electrolytic solution and the first electrolytic solution positioned between the anode liquid compartment and the cathode liquid compartment. 2 An anion exchange film configured to exhibit ionic conductivity with an electrolytic solution, having a thickness of less than 100 μm, and with respect to at least one of the first cation species and the second cation species. The step of preparing the flow battery and the step of instructing the flow battery to be charged, which comprises the anion exchange membrane having a constant diffusion rate of less than 0.4 ppm / hour / cm ^2. How to prepare. The method of claim 18, further comprising a step of instructing the flow battery to be charged by electrically connecting the flow battery to a variable energy source. The method of claim 18, further comprising a step of instructing the flow battery to be electrically connected to a high voltage current (HVDC) transmission line. The method according to claim 20, further comprising a step of instructing to replace at least one of the first electrolytic solution and the second electrolytic solution after the flow battery is discharged. In the method of producing an anion exchange membrane
A step of integrating a cationic functional monomer having a cross-linking group into a polymerization product having almost no cross-linking agent, and a step of coating a microporous substrate having a thickness of less than about 100 μm with the polymerization product. How to prepare. The method according to claim 22, wherein the microporous substrate has a thickness of about 25 μm. The method of claim 25, wherein the microporous substrate comprises at least one of polypropylene, high molecular weight polyethylene, ultra high molecular weight polyethylene, polyvinyl chloride, polyvinylidene chloride, polysulfone, and combinations thereof. The method of claim 24, wherein the microporous substrate has a porosity between about 25% and 45% and an average pore diameter between about 50 nm and about 10 μm. The method according to claim 25, wherein the microporous substrate is made of ultra-high molecular weight polyethylene having a porosity of about 35% and an average pore diameter of about 200 nm.